Cycles Color Problem
This might be a lighting problem. Do you have a colored light in your scene?
If none of your lights contain any Yellow, only the other colors will be reflected by the Material
EDIT:
I figured it out.
The part with the problem has multiple surfaces inside of each other.
I dragged them apart and apparently this part exists 8 times. With the pink material on 6 of the instances.

This sometimes happens unnoticed, when proportional editing is turned on, because it makes you move all the objects at once.
Proportional editing (for those who don't know) is this option:

Turn it off, point at the problematic part, hit L and then drag your selection away and you will see.
;)